The invention relates to dispenser equipment specifically adapted for serially dispensing incompatible chemicals. Incompatible chemicals are defined as liquid chemicals that when mixed can result in creation of an undesirable reaction by-product. The dispenser combines safety features that ensure that the appropriate chemicals are attached to the appropriate input directed to a pumping station and that the dispenser cannot simultaneously dispense incompatible liquid streams and that after the pumping of a liquid stream is complete, the pump is not used again until the pump and manifold are flushed.
Automatic dispensers that provide a liquid or fluid chemical solution to a use locus with little or no supervision have been common in the art. Such chemical dispensers are used in warewashing, laundry, hard surface cleaning, textile processing including the processing of thread and yarn, etc. Many such dispenser apparatus deliver chemical compositions to a use locus in a series of process treatment steps, wherein each treatment step requires a different kind of chemical. Such chemicals can include organic surfactants, nonionic rinse aids, acid compositions, alkaline compositions, chlorine bleach compositions, alkaline materials and a variety of other cleaning or treating materials. Often such materials have substantial functionality when used appropriately in a use locus, however, if mixed with another incompatible chemical, such a mixture can result in the production of an undesirable reaction by-product that can interfere either with the operation of the use locus, the operation of the dispenser or can interfere with or ruin the substrate present in the machine such as ware, laundry, textile or other materials. Further, some chemicals if mixed can be explosive or toxic. Mixing acid and a source of chlorine can result in the release of chlorine gas. Blending certain chemicals can also result in the release of hydrogen gas which can also have explosive consequences.
A number of such chemical systems are known in the art. For example, Kirschmann et al., U.S. Pat. No. 4,691,850, show a chemical dispensing system that involves liquid tote containers that are directly connected through tube-like inputs to a manifold for distribution to a use locus. Bird et al., U.S. Pat. No. 4,627,457, show a plurality of distribution manifolds connected to apparatus that can dilute product and distribute the product in an appropriate manifold. Copeland et al., U.S. Pat. No. 4,845,965, show a method to convert a solid product into a liquid concentrate for delivery to a use locus. Similarly, Lehn, U.S. Pat. No. 4,858,449, shows an apparatus that can provide a liquid concentrate from a solid block detergent dispensed from a dispenser unit. Turner et al., U.S. Pat. No. 5,014,211, show a dispenser apparatus controlled within an electronic controller that draws chemical from a source through a series of pumps, a single conduit, a selected locus from a set of use loci. Proudman, U.S. Pat. No. 5,246,026, similarly shows dispensing three or more liquid chemicals through dedicated pumps to a common dilution manifold under the direction of a system controller. Beldham, U.S. Pat. No. 5,390,385, shows an electronically controlled pumping system that can dispense a liquid chemical to a use locus under the control of a preprogrammed sequence. Lastly, Livingston et al., U.S. Pat. No. 5,392,618, dispenses chemicals from a drum source using individual pumps to separate manifolds directed to a use locus such as a laundry machine.
The prior art generally dispenses a liquid chemical from a source reservoir through a line to a pump which is then directed to either a common or a separate manifold that ends in a use locus. Connecting an inappropriate source of chemical to an incorrect line can result in contacting reactive liquids in the dispenser or use locus with the production of an undesirable reaction by-product that can be damaging or hazardous.
A substantial need exists for a dispenser apparatus that can prevent inappropriate contact between incompatible chemicals, thereby preventing the concomitant production of a harmful by-product. Such a dispenser will prevent the simultaneous dispensing of two incompatible chemicals, will prevent dispensing a liquid chemical through a manifold contaminated by an incompatible chemical and will prevent the inappropriate connection of a reservoir of a chemical to a manifold intended for an incompatible chemical. The prior art as a whole fails to provide such a dispensing device.
Accordingly, the invention is found in a dispenser apparatus that can provide two or more liquid chemical streams to a use locus, said chemical streams comprising incompatible streams such that upon mixing of the streams can result in the production of an undesirable reaction by-product in the mixed stream, the dispenser comprising a common manifold equipped with a fluid inlet, said manifold leading to an outlet connected to a container or use locus; a pumping station in liquid communication with the fluid inlet; at least two liquid inputs to the pumping station, each input having a coupling that can fit only a reservoir for an appropriate liquid chemical for that inlet; and an electromechanical controller that prevents the dispenser from pumping simultaneously different chemical streams to the manifold and also prevents pumping a liquid chemical into the manifold without an intermediate liquid or aqueous flush to remove residue of an incompatible liquid chemical. For the purposes of this disclosure the term incompatible chemical indicates a chemical, with reference to another chemical in a system, that produces an undesirable by-product, when mixed and as a result loses some substantial degree of function. Minor physical and chemical changes in the chemical that do not result in loss of function is not an indicia of incompatibility. Such incompatibility is shown in systems that form a precipitate that has no activity in the use locus; in systems that form a harmful gas such as chlorine (Cl2), hydrogen (H2), etc.; in systems that destroy the activity of a useful component such as a surfactant, an enzyme, a bleach, etc. or cause an undesirable phase separation in a chemical formulation. Such incompatibility results in a chemical or composition of the chemical that has reduced activity in a use locus. Conventional effects common in the use of chemicals in the use locus such as dissolution, dilution, ionization, mere color change without more, do not constitute chemical incompatibility.